In the burning of all fluid fuels, there is concern for stability of burning and the speed with which the fuels burn. Rapid and stable burning of fuels of substantially any type has been a constantly sought goal since fuel burners were first invented. It is well known in the art of the burning of fluid fuels that the highest possible initial flame temperature is the key to both the speed of the burning of fuels and the stability with which the fuels burn. Means for production of highest initial flame temperature permit the burning of normally wasted calorific value fuels; and because of this, further conservation of heat energy is achieved.
The use of regenerative tile structures with burner apparatus has proven effective in the past as a means of obtaining the desired self-sustaining and rapid combustion of fuels. The basic operating principle behind these structures is to provide a sufficiently high flame temperature for effective fuel combustion. Such flame temperatures are maintained by combustion of the fuel within a refractory lined zone for heat retention and the recirculation of hot flame gases through the zone.
One such apparatus is disclosed in the U.S. Pat. No. 3,711,243, assigned to the John Zink Company. In this invention, atomized fuel is sprayed into a cylinder burning zone encased by an annular shaped ceramic tile. A second ceramic member having a downstream face disposed at right angles to the axis of the first ceramic tile is positioned adjacent the upstream end of the first tile and provides a central opening for fuel injection and the aspiration of air to the combustion zone. The downstream face of the second ceramic member serves to guide recirculating hot flame gases to the entering air stream, thus increasing the flame temperature.
Under certain combustion conditions, it becomes necessary to direct a flow of air immediately along the downstream face of the first annular tile to prevent the deposition of carbon. To accomplish this result, it is required that the second ceramic member be of slightly smaller outside diameter than the inner diameter of the first tile, thus forming an annular passageway for air.
Although the aforementioned apparatus is effective, it is apparent that a simplified design would lessen construction costs and improve the flame temperature increase to thereby enhance the value of the invention to the public.
Furthermore, the guided re-entry of hot gases into the air-fuel mixture at right angles dilutes the entering air supply, thereby retarding the initial fuel combustion reaction and lessening the desired effect of flame temperature increase due to recirculation on flame temperature.